Python Serial:如何使用 read 或 readline 函数一次读取 1 个以上的字符 [英] Python Serial: How to use the read or readline function to read more than 1 character at a time
问题描述
我无法使用我的程序读取多个字符,我似乎无法弄清楚我的程序出了什么问题.
I'm having trouble to read more than one character using my program, I can't seem to figure out what went wrong with my program.
import serial
ser = serial.Serial(
port='COM5',\
baudrate=9600,\
parity=serial.PARITY_NONE,\
stopbits=serial.STOPBITS_ONE,\
bytesize=serial.EIGHTBITS,\
timeout=0)
print("connected to: " + ser.portstr)
count=1
while True:
for line in ser.read():
print(str(count) + str(': ') + chr(line) )
count = count+1
ser.close()
这是我得到的结果
connected to: COM5
1: 1
2: 2
3: 4
4: 3
5: 1
其实我很期待这个
connected to: COM5
1:12431
2:12431
像上面提到的那样可以同时读取多个字符而不是一个一个.
something like the above mentioned which is able read multiple characters at the same time not one by one.
推荐答案
我看到了几个问题.
首先:
ser.read() 一次只返回 1 个字节.
ser.read() is only going to return 1 byte at a time.
如果您指定计数
ser.read(5)
它将读取 5 个字节(如果在 5 个字节到达之前发生超时,则更少.)
it will read 5 bytes (less if timeout occurrs before 5 bytes arrive.)
如果您知道您的输入总是以 EOL 字符正确终止,更好的方法是使用
If you know that your input is always properly terminated with EOL characters, better way is to use
ser.readline()
这将继续读取字符,直到收到 EOL.
That will continue to read characters until an EOL is received.
第二:
即使你得到 ser.read() 或 ser.readline() 返回多个字节,由于您正在迭代返回值,因此您将仍然一次处理一个字节.
Even if you get ser.read() or ser.readline() to return multiple bytes, since you are iterating over the return value, you will still be handling it one byte at a time.
摆脱
for line in ser.read():
然后说:
line = ser.readline()
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